1. Field of the Invention
The present invention relates generally to a cantilever shaft assembly having a shaft body made from a synthetic resin and rotatably supporting a rotating member such as a power transmission sprocket or a power transmission pulley. More particularly, this invention relates to such a cantilever shaft assembly which is particularly suitable for use in a water-treatment sludge scraping apparatus or a plating dross collecting and removing apparatus.
2. Description of the Related Art
Conventional cantilever shafts, as shown in FIG. 6, include a free end portion X rotatably supporting thereon a rotating member such as a driven sprocket S, and a flanged body portion X2 adapted to be attached to the surface of a stationary supporting member. To reduce the weight and improve the corrosion resistance, the cantilever shaft X is molded from a synthetic resin material into a one-piece structure. The synthetic resin molded cantilever shaft X is used in a sludge scraping machine disclosed in Japanese Utility Model Laid-open Publication No. (HEI) 2-57109 and Japanese Patent Laid-open Publication No, (HEI) 3-96711.
To secure reliable and firm attachment to the supporting member such as a wall, the synthetic resin molded cantilever shaft has a specific cone-like configuration consisting of the free end portion X1 of reduced diameter and the flanged body portion X2 of enlarged diameter.
The conventional cantilever shaft has varius drawbacks as enumerated below.
(1) Due to its specific cone-like configuration, the conventional cantilever shaft requires a special molding die which is expensive to manufacture. Because of a little demand, the cantilever shaft is not suited for mass-production. Thus, the manufacturing cost of the conventional cantilever shaft is relatively high.
(2) The synthetic resin cantilever shafts molded on the same molding die have a fixed length. Accordingly, when used in an application where different lengths of cantilever shafts are necessary to form various types of water treatment sludge scraping apparatuses, a corresponding number of molding dies must be provided. The thus formed synthetic resin cantilever shafts are highly expensive to manufacture.
(3) When the free end portion rotatably supporting the rotating member is damaged or worn out, the conventional cantilever shaft, due to its one-piece structure, must be replaced for repairing as a whole including the undamaged body portion. Replacement of the overall structure is inefficient, laborious and time-consuming.
(4) To replace the partially damaged synthetic resin cantilever shaft with a new cantilevered shaft is wasteful of resources and requires an adequate waste disposal treatment to avoid environmental contamination.